Enoxacin (CI-919) was evaluated for activity against 120 multiply resistant clinical isolates of the family Enterobacteriaceae and Pseudomonas aeruginosa. The MIC of enoxacin for 95% of the strains tested was less than or equal to 2 micrograms/ml. Approximately 90% of the isolates were susceptible to enoxacin, norfloxacin, ceftazidime, moxalactam, cefotaxime, cefoperazone, and amikacin. Marked resistance to the other seven antimicrobial agents tested was observed.